I'm brand new to this forum. Thanks for inviting me. I do O gauge. I'm looking or an inexpensive way to ballast my Atlas O track. I've considered chicken grit, which by the way, looks like perfect ballast in terms of size and color. BUT . . . it contains lots of different ingredients, including a variety of oxides, including zinc, copper, and mannganous. Although this ballast will be stabilized with glue/water, I am wondering whether any ambient dust from these oxides could cause rust to engines and consists. Any knowledge on this or other ideas or suggestions?

I dont know if you have heard of screens?? It is a mixture of rocks that are about the same size as chicken grit and looks like rocks, well because it is rocks. I know they come in bulk such as truck loads (obviously to much)LOL, but I believe hardware stores have them in maybe 25 lb bgs.
Dont know if that will help? Good luck to you